Setmelanotide

BACKGROUND: A phase 2 trial of setmelanotide, a melanocortin-4 receptor agonist, showed substantial weight loss in patients with acquired hypothalamic obesity, but additional data are needed. METHODS: We conducted a phase 3 trial in which participants were randomly assigned in a 2:1 ratio to receive setmelanotide (at a dose of 1.5 to 3.0 mg) or placebo administered subcutaneously once daily for 52 weeks after a dose-escalation period. Persons at least 4 years of age were potentially eligible for the trial if they had acquired hypothalamic obesity, which was defined by a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) that was at or above the 95th percentile for age and sex (for participants <18 years of age) or at least 30 (for participants ≥18 years of age) and a history of a hypothalamic tumor, lesion, or injury. The primary end point was the mean percent change in BMI from baseline to 52 weeks after the end of the dose-escalation period. Secondary end points included the mean change in the weekly average of the maximal daily hunger score (range, 0 to 10, with higher scores indicating more severe hunger), assessed in participants at least 12 years of age. RESULTS: From April 26, 2023, to March 18, 2025, a total of 120 participants were assigned to receive setmelanotide (81 participants) or placebo (39 participants). The mean (±SD) age was 19.9±13.8 years (range, 4 to 66). Among participants 18 years of age or older, the mean BMI was 41.2±9.7; the mean BMI z score among those younger than 18 years of age was 3.61±1.66. The least-squares mean (LSM) change in BMI at 52 weeks was -16.5% (95% confidence interval [CI], -19.3 to -13.8) with setmelanotide and 3.3% (95% CI, -0.6 to 7.2) with placebo (P<0.001), and the LSM change in the weekly average of maximal daily hunger scores was -2.73 (95% CI, -3.28 to -2.18) in the setmelanotide group and -1.45 (95% CI, -2.23 to -0.67) in the placebo group (P = 0.009). Adverse events were reported in 100% of the participants in the setmelanotide group and in 90% of those in the placebo group, and serious adverse events were reported in 28% and 8%, respectively. The most common adverse events with setmelanotide were skin hyperpigmentation, nausea, vomiting, and headache. CONCLUSIONS: Setmelanotide led to significantly greater reductions in BMI and hunger than placebo at 52 weeks among participants 4 to 66 years of age with acquired hypothalamic obesity. (Funded by Rhythm Pharmaceuticals; TRANSCEND ClincialTrials.gov number, NCT05774756.).

BACKGROUND: Smith Magenis Syndrome (SMS) is a rare genetic disorder caused by RAI1 haploinsufficiency. Obesity in people with SMS is believed partially due to dysfunction of the proximal melanocortin 4 receptor (MC4R) pathway. We therefore studied effects of treatment with the MC4R agonist setmelanotide on obesity and hunger, as well as metabolic, cardiac and safety, in individuals with SMS. METHODS: People with SMS received once-daily setmelanotide injections, with the dose titrated bi-weekly to a maximum of 3 mg over ∼1 month; and a full-dose treatment duration of 3mo. The primary outcome was percent change in body weight. Secondary outcomes included hunger, waist circumference, body composition, and safety. RESULTS: 12 individuals, ages 11-39 y, enrolled and 10 completed the full-dose treatment phase. Mean percent change in body weight at end-treatment was - 0.28 % [(95 % CI, -2.1 % to 1.5 %; n = 12; P = 0.66]. Participants experienced a significant decrease in total cholesterol associated with a significant decrease in HDL-cholesterol and a trend for lower LDL-cholesterol. Self-reported hunger was reduced at end-treatment (p = 0.011). All participants reported adverse events (AEs), most commonly injection-site reactions and skin hyperpigmentation. No AEs led to withdrawal or death. CONCLUSIONS: In this trial, setmelanotide did not significantly reduce body weight in participants with SMS. Participants reported significant differences in hunger, but such self-reports are difficult to interpret without a placebo-treated group. The changes in lipid profiles require further investigation. Results of this study do not suggest that dysfunction of the proximal MC4R pathway is the main etiology for obesity in people with SMS.

BACKGROUND: Hypothalamic obesity resulting from hypothalamic damage might affect melanocortin signalling. We investigated the melanocortin-4 receptor agonist setmelanotide for treatment of hypothalamic obesity. METHODS: This phase 2, open-label, multicentre trial was done in five centres in the USA. Eligible patients were aged between 6 and 40 years with obesity and history of hypothalamic injury or diagnosis of a non-malignant tumour affecting the hypothalamus that was treated with surgery, chemotherapy, or radiation. Setmelanotide was titrated up to a dose of 3·0 mg and administered subcutaneously once a day for a total duration of 16 weeks. The primary endpoint was the proportion of patients with a reduction in BMI of at least 5% from baseline after 16 weeks, compared with a historic control rate of less than 5% in this population. The primary endpoint was analysed using the full analysis set, which includes all patients with baseline data who received at least one dose of setmelanotide. Safety was assessed in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov (NCT04725240) and is complete. FINDINGS: Between June 6, 2021, and Jan 13, 2022, 19 patients were screened for inclusion. One patient was excluded, and 18 were enrolled and received at least one dose of setmelanotide. Patients were primarily White (n=14 [78%]) and male (n=11 [61%]). Enrolled patients had a mean age of 15·0 years (SD 5·3) and a mean BMI of 38·0 kg/m2 (SD 6·5). Of 18 patients enrolled, 16 (89%) of 18 patients completed the study and met the primary endpoint of reduction in BMI of at least 5% from baseline after 16 weeks (p<0·0001). The mean reduction in BMI across all patients was 15% (SD 10). A composite proportion of patients had a clinically meaningful change (89%, 90% CI 69-98%; p<0·0001), comprising a reduction in BMI Z score of at least 0·2 points for patients younger than 18 years (92%, 68-100%; p<0·0001) and reduction in bodyweight of at least 5% for patients aged 18 years or older (80%, 34-99%; p<0·0001). Patients aged 12 years or older had a mean reduction in hunger score of 45%. Frequent adverse events included nausea (61%), vomiting (33%), skin hyperpigmentation (33%), and diarrhoea (22%). Of 14 patients who continued treatment in a long-term extension study (NCT03651765), 12 completed at least 12 months of treatment at the time of publication and had a mean change in BMI of -26% (SD 12) from index trial baseline. INTERPRETATION: These findings support setmelanotide as a novel effective treatment of hypothalamic obesity. FUNDING: Rhythm Pharmaceuticals.

BACKGROUND: Setmelanotide, a melanocortin-4 receptor (MC4R) agonist, has been shown to reduce hunger and weight in patients aged 6 years and older with proopiomelanocortin (POMC) deficiency (including biallelic variants in proprotein convertase subtilisin/kexin type 1 [PCSK1]), leptin receptor (LEPR) deficiency, or Bardet-Biedl syndrome (BBS). No approved therapies for patients younger than 6 years old currently exist. The phase 3, open-label VENTURE trial aimed to evaluate the efficacy and safety of setmelanotide in patients aged 2-5 years with POMC or LEPR deficiency or BBS. METHODS: This phase 3, open-label, multicentre trial, conducted across six sites in the USA, the UK, Spain, and Australia, enrolled eligible patients aged 2-5 years who had hyperphagia and obesity due to biallelic POMC (including PCSK1) or LEPR variants or genetically confirmed BBS. Open-label subcutaneous setmelanotide was administered once daily for 52 weeks, starting at 0·5 mg with doses increasing every 2 weeks in 0·5 mg increments until reaching the maximum dose based on weight. The co-primary endpoints at week 52 were the percentage of patients reaching a 0·2-point decrease or greater in BMI Z score (a statistical measure used to assess BMI in paediatric patients considering a patient's BMI and comparing it to reference values for the same age and sex) and mean percent change in BMI. Additional endpoints measured safety, hunger, weight-related outcomes, and caregiver burden. The study is registered at ClinicalTrials.gov (NCT04966741) and is complete. FINDINGS: Between March 8, 2022, and Sept 18, 2023, 13 patients were screened at the six sites, and 12 patients were enrolled in the study (seven with POMC or LEPR and five with BBS); one patient with BBS was excluded as their BMI was not at the 97th percentile or above. Of the 12 patients enrolled, most were male (seven [58%] vs five [42%] for female) and the mean age was 3·6 years (SD 0·9). 11 patients completed the trial. Ten (83%) of the 12 overall participants reached a 0·2-point reduction or more in BMI Z score per WHO methodology at week 52 (95% CI 58·7-99·8). The mean percent change in BMI from baseline at week 52 was -18% (SD 13) in the overall safety population. Mean percent change in BMI at week 52 was -26% (SD 11) in patients with POMC or LEPR deficiency and -10% (9) in patients with BBS. Mean reductions in secondary endpoints of BMI Z score (3·4 [2·5]) and percent of the BMI 95th percentile (32·5 [22·9]) were seen at Week 52. 91% of caregivers reported that patients were less hungry than at baseline. All adverse events were mild or moderate; skin hyperpigmentation, vomiting, nasopharyngitis, upper respiratory tract infection, and injection site reactions were most common. No serious adverse events or adverse events leading to study discontinuation or death were reported. INTERPRETATION: To our knowledge this is the first trial of setmelanotide in patients younger than 6 years old. These results support the benefit of the drug as an early intervention to manage obesity in this population. FUNDING: Rhythm Pharmaceuticals.

BACKGROUND: Impaired cilial signalling in the melanocortin-4 receptor (MC4R) pathway might contribute to obesity in patients with Bardet-Biedl syndrome and Alström syndrome, rare genetic diseases associated with hyperphagia and early-onset severe obesity. We aimed to evaluate the effect of setmelanotide on bodyweight in these patients. METHODS: This multicentre, randomised, 14-week double-blind, placebo-controlled, phase 3 trial followed by a 52-week open-label period, was performed at 12 sites (hospitals, clinics, and universities) in the USA, Canada, the UK, France, and Spain. Patients aged 6 years or older were included if they had a clinical diagnosis of Bardet-Biedl syndrome or Alström syndrome and obesity (defined as BMI >97th percentile for age and sex for those aged 6-15 years and ≥30 kg/m2 for those aged ≥16 years). Patients were randomly assigned (1:1) using a numerical randomisation code to receive up to 3·0 mg of subcutaneous setmelanotide or placebo once per day during the 14-week double-blind period, followed by open-label setmelanotide for 52 weeks. The primary endpoint, measured in the full analysis set, was the proportion of patients aged 12 years or older who reached at least a 10% reduction in bodyweight from baseline after 52 weeks of setmelanotide treatment. This study is registered with ClinicalTrials.gov, NCT03746522. FINDINGS: Between Dec 10, 2018, and Nov 25, 2019, 38 patients were enrolled and randomly assigned to receive setmelanotide (n=19) or placebo (n=19; 16 with Bardet-Biedl syndrome and three with Alström syndrome in each group). In terms of the primary endpoint, 32·3% (95% CI 16·7 to 51·4; p=0·0006) of patients aged 12 years or older with Bardet-Biedl syndrome reached at least a 10% reduction in bodyweight after 52 weeks of setmelanotide. The most commonly reported treatment-emergent adverse events were skin hyperpigmentation (23 [61%] of 38) and injection site erythema (18 [48%]). Two patients had four serious adverse events (blindness, anaphylactic reaction, and suicidal ideation); none were considered related to setmelanotide treatment. INTERPRETATION: Setmelanotide resulted in significant bodyweight reductions in patients with Bardet-Biedl syndrome; however, these results were inconclusive in patients with Alström syndrome. These results support the use of setmelanotide and provided the necessary evidence for approval of this drug as the first treatment for obesity in patients with Bardet-Biedl syndrome. FUNDING: Rhythm Pharmaceuticals.

Objective: To review clinical data regarding the newly approved drug setmelanotide, an injectable melanocortin 4 receptor (MC4R) agonist, for chronic weight management in adults and children aged 6 years and older with monogenic obesity. Data Sources: A literature review was performed by searching MEDLINE, SCOPUS, and EMBASE for all relevant English-language articles published between January 1, 1996, and November 30, 2021, using search terms obesity, setmelanotide, Imcivree, and MC4R agonist. Study Selection/Data Extraction: This review included two phase 2, two phase 3, and one ongoing clinical trial evaluating the efficacy and/or safety of setmelanotide. Data Synthesis: Setmelanotide demonstrates statistically significant weight loss with at least a 10% decrease in body weight after 1 year and decreased appetite in phase 2 and phase 3 clinical trials. The most common adverse effects included injection site reaction (96%), skin hyperpigmentation (78%), nausea (56%), headache (41%), and diarrhea (37%). Place in Therapy: Setmelanotide is the first and only Food and Drug Administration-approved medication for the treatment of proopiomelanocortin, proprotein convertase subtilisin/kexin type 1, and leptin receptor deficiency in patients with obesity. It may be used in children and adults who have received genetic testing and exhibited extreme obesity before age five. Setmelanotide is a daily subcutaneous injection and may be difficult to afford for patients. Conclusion: Setmelanotide is an effective treatment in patients with obesity and indicated genetic disorders.